The CPI today strongly criticised the anti-terror probe agency NIA for not being able to provide "credible evidence" in the 2007 Mecca Masjid blast case, which resulted in acquittal of all five accused in the case.

Lashing out at the NIA probe into the Mecca Masjid blast which had left nine persons dead and 58 others injured, the Left party questioned the agency for its "failure" to establish the truth behind the blast.

"The NIA court has acquitted all the accused for lack of credible evidence. But who are the people who did it? Who are the forces behind the blast? That should be found out," CPI leader D Raja told PTI.

"The fact remains that there was an attack. People should know who were behind such attacks. Lets see what the government does or the investigating agency does.. NIA completely failed to establish the truth behind the blast," Raja said.

A special anti-terror court in Hyderabad acquitted right-wing activist Swami Aseemanand and four others today in the 2007 Mecca Masjid blast case, ruling that the prosecution has failed to prove charges against them.

A massive blast had ripped through the Mecca Masjid on May 8, 2007 during Friday prayers, killing nine people and wounding 58.

Aseemanand's counsel, J P Sharma, told reporters after the verdict by a special NIA court that "the prosecution failed to prove allegations against the five accused who faced trial in the case and, hence, the court acquitted them."

Ten persons were named as accused in the case but only five of them were arrested and sent up for trial.